Shoulder surfing is a method used by attackers to obtain confidential or sensitive information by visually observing someone's computer screen, mobile device, or keypad without their knowledge or consent. The attacker positions themselves strategically, often standing close to the victim, in order to see passwords, PIN numbers, credit card details, or any other private information being entered. Shoulder surfing can occur in public places, such as cafes, airports, or crowded areas, where individuals may unknowingly expose their screens or keypads to prying eyes.